1.0 Field of the Invention
The present invention is directed to vehicles for transporting a payload and, more particularly, to a multicombination vehicle for transporting a payload, such as a mined ore, over the roadways in an underground mine. The multicombination vehicle includes at least one powered, load-carrying towing unit and at least one load-carrying towed unit. The multicombination vehicle is configured to minimize the swept path width of the vehicle to permit operation within the relatively narrow tunnels and included relatively low radius turns typically found in underground mines.
2.0 Related Art
Mined payloads, such as various metal ores, are typically transported through the tunnels of an underground mine by either a railway train including a locomotive and one or more cars operating on a fixed system of railway tracks, or rigid body, load-carrying trucks. Although each known system may be advantageously utilized in certain applications, they are both subject to various disadvantages.
An underground railway system is relatively expensive to install and operate due to the cost of acquiring the locomotive and installing the fixed railway system and the associated maintenance costs. Furthermore, and perhaps more importantly, an underground railway system is route-specific and therefore not flexible to changes in route without incurring the expense of installing additional railway tracks. Underground mines typically have several mining areas, which may occur on multiple levels within the mine. The mined product, such as ore, is typically transported from each mining area to a common receiving area, and then through one or more vertical chutes connecting different levels of the mine if required, to a central processing area where the ore is processed, or sufficiently crushed. The ore is then typically removed from the mine through a single vertical shaft extending to the surface. A single ore crusher and associated shaft is typically used due to the prohibitive costs associated with drilling a shaft from the surface to the mining area deep below the ground. As each new mining area opens, it is necessary to incur the cost of installing new track for the railway system, or to use supplemental vehicles to haul the ore from the mining area to the end of the railway track system.
Rigid body load-carrying trucks, such as wheeled dump trucks, are not route-specific since they are capable of traveling over various roadways within the mine between various origination and destination points. However, known trucks of this type are typically designed for hauling loads over relatively short distances and rough terrain, such as that which may be experienced in above-ground applications. Accordingly, such trucks are typically designed with relatively large tires for relatively slow speed operation and are relatively expensive to operate and maintain due to fuel and tire costs. The efficiency of these vehicles typically decreases as the hauling distance increases. Furthermore, a single rigid body truck of this type has a significantly lower payload capacity as compared to the multicombination vehicle of the present invention.
Multicombination vehicles commonly referred to as "road trains" have been in use for some time, particularly in Australia, for the purpose of hauling mined products, or the commodities of other industries, over above-ground roadways. Known "road trains" typically include a powered load-carrying towing vehicle such as a wheeled, rigid body truck and one or more load-carrying towed vehicles. The towed vehicles may include a wheeled dolly and a semi-trailer coupled to the dolly. Both the towing and towed vehicles may include load-carrying bodies of the side-tipping type. However, conventional "road trains" are typically designed for use at relatively high speed, for instance at speeds up to 55-60 mph, and are therefore not capable of operating in an underground mine for the following reasons. Due to the relatively high speed, straight-down-the-road application of known above ground road trains, the mechanical coupling between each adjacent pair of vehicles is located as far forward as possible, or as close to the rear suspension of the upstream or forward vehicle, within the physical constraints imposed in a turning situation by the tow bar connecting the vehicles (i.e., to avoid contact between the tow bar and the chassis of the forward vehicle when turning). This location of mechanical couplings between each adjacent pair of vehicles is required to maintain the side-to-side sway, or yaw, of the last vehicle within acceptable limits for aboveground, over-the-road application, but is not compatible for operation within an underground mine due to the relatively low operating speeds as well as the relatively narrow tunnels and small radius bends experienced in underground mines. The inventor is unaware of any known above ground, road-legal multicombination vehicle of the type just described, which is capable of gaining access to an underground mine and operating within the profiles of the mine as typically exists in underground mines throughout the world.
In view of the foregoing disadvantages and limitations associated with known load-carrying vehicles, a commercial need exists for an improved load-carrying vehicle for use in underground mines.